2: Acute Mesenteric Ischaemia, Chronic Mesenteric Ischaemia, Abdominal Trauma Flashcards
What is acute mesenteric ischaemia
Sudden decrease in blood supply to the bowl that can cause infarction
What are the 4 types of acute mesenteric ischaemia
- Acute mesenteric arterial thrombosis
- Acute mesenteric arterial embolism
- Venous congestion
- Non-occlusive ischaemia
If ischaemia due to thrombosis in situ what is it called
Acute mesenteric arterial thrombosis (AMAT)
if ischaemia is due to embolism in situ what is it called
Acute mesenteric arterial embolism (AMAE)
What is a cause of acute mesenteric arterial thrombosis
Atherosclerosis
What are 5 causes acute mesenteric arterial embolism
- AF
- AAA
- Thoracic AA
- Mural thrombus
- Prosthetic heart valve
What are 2 causes of non-occlusive mesenteric ischaemia
- Cardiogenic shock
2. Hypovolaemic shock
What are 3 causes of venous occlusion
- Coagulopathy
- Thrombophilia
- Malignancy
What are risk factors for AMAT and AMAE
Cardiovascular RF: Smoking Alcohol HTN Hypelripidaemia
How does acute mesenteric ischaemia present
- Pain out of proportion to clinical findings
- Diffuse, generalised abdominal pain
- N+V
What investigations are ordered for acute mesenteric ischaemia
- ABG
- CT scan with contrast
- CXR
What will be seen on ABG
- High lactate
- Metabolic acidosis
What imaging is used to definitely diagnose acute mesenteric ischaemia
CT with IV contrast
When is a CXR performed
If perforation is suspected
How is mesenteric ischaemia managed
IV Fluids
Broad-spec antibiotics
Surgery for re-vascularisation (with re-look 24-48h after)
Revascularisation
What are 3 complications of mesenteric ischaemia
Bowel necrosis
Bowel perforation
Short-gut syndrome post-resection
What is chronic mesenteric ischaemia
reduced blood supply to the bowel due to atherosclerosis
In which individuals does chronic mesenteric ischaemia occur
Elderly patients
What are 4 risk factors for chronic mesenteric ischaemia
Smoking
Hyperlipidaemia
HTN
DM
How does chronic mesenteric ischaemia present
Post-prandial pain (10m-4h)
Weight loss
Explain pathophysiology of chronic mesenteric ischaemia
- Due to atherosclerosis of two blood vessels (SMA, IMA, Coeliac trunk). Due to collateral blood supply it must be 2.
- Bowel receives sufficient oxygen at rest, however, struggles during increased demand: such as post-digestion.
What is first-line investigation for chronic mesenteric ischaemia
CT angiography
What is gold-standard for acute mesenteric ischaemia
CT with contrast
What is used to manage chronic mesenteric ischaemia
Modify risk factors
Endovascular repair = mesenteric angioplasty
Which sites are vulnerable to ischaemia and why
Watershed areas:
Splenic flexure and rectosigmoid junction
- due to switch in blood supply
Define acute mesenteric ischaemia
ischaemia of the small intestine
Define ischaemic colitis
ischaemia of the large intestine
What causes ischaemic colitis
caused by global hypo perfusion caused by:
- Hypotension
- Hypovolaemia
- Thrombophillia
how does ischaemic colitis present
Presents in 3 phases
- Hyperactive
- Paralytic
- Shock
how does the hyperactive phase of ischaemic colitis present
Colicky abdominal pain in the LIF.
how does the paralytic phase of ischaemic colitis present
- Diffuse abdominal pain
- Bloating
- Absent bowel sounds
how does the shock phase of ischaemic colitis present
- Acute abdomen
- Guarding
- Rebound tenderness
how is acute mesenteric ischaemia investigated
CT W/constrast
how is ischaemic colitis investigated
CT angiography
how is ischaemic colitis managed
IV Fluids
Antiplatelets
- If necrotic may require resection
What are the two types of abdominal trauma
- Blunt trauma
- Penetrating
What is blunt trauma
Blunt force to the body - does not penetrate skin.
What is penetrating trauma
Penetrates the skin.
What are 3 causes of blunt trauma
- RTA
- Falls
- Deceleration injuries or external crushing
What are 2 causes of penetrating trauma
- Gunshot wounds
- Stabbing
What is the most common injury following blunt trauma
Splenic rupture (40%)
What are 5 other injuries that can occur due to abdominal trauma
- Liver haematoma
- Pancreatic contusion
- Intra-abdominal bleeding due to fracture ribs causing injury
- Traumatic injury to bladder and kidney
- Duodenal injury and haematoma
- Pelvic fracture
Why may blunt trauma cause intra-abdominal bleeds
Due to causing fracture of ribs - which are able to penetrate intra-abdominal organs
What type of injury pancreatic contusion
Handlebar - trauma to epigastric region
How will pancreatic contusion present clinically
Epigastric pain
N+V
Anorexia
Fever
What is a common injury in children who suffer blunt abdominal trauma
Duodenal haematoma
How will splenic rupture present
Hypotension - dizziness, syncope
Left hypogastric pain
Left shoulder irritation
How will liver haematoma present clinically
Ecchymosis of the right chest - pain referred to right shoulder
What is the most common site for gunshot wound to injure
Small bowel
What is the most common site for stab wound to injure
Liver
Explain signs of intra-abdominal bleeding
- Hypotension
- Tachycardia
- Discolouration flanks
- Shock
- Rigid abdomen
- Abdominal distention
For blunt trauma, what is used pre-hospital to manage patients
ATLS
: any resuscitation required is undertaken
What imaging is used for blunt trauma
FAST scan
Focused assessment with sonography for trauma
What is FAST scan used to detect
Haemoperitoneum (intra-abdominal bleeding)
If FAST scan is unavailable, what should happen to blunt abdominal trauma patients
Taken immediately to theatres
If patient is stable and FAST scan is inconclusive what imaging is used
CT scan
If patient is unstable and FAST scan inconclusive, what imaging is used
Diagnostic peritoneal lavage
Explain diagnostic peritoneal lavage
Surgical investigation:
- Incision made into abdomen
- Catheter inserted and fluid aspirate
- If blood aspirated, Hartmann’s solution is inserted and left for 5 minutes - then removed and sent for analysis
What is second-line to FAST scan for investigaitng abdominal trauma
Laparotomy
What are 3 indications of laparotomy
- Haemodynamic instability
- Clinical peritonitis
- Intra-abdominal bleed detected on imaging
What does management of abdominal trauma depend on
Site of injury
How is pancreatic injury managed
Percutaneous drainage
How is duodenal injury managed
NG tube and parental nutrition
How are individuals with penetrating trauma managed in pre-hospital enviorment
ATLS
What is important for penetrating trauma
- Tetanus prophylaxis
- Antibiotics
How is penetrating trauma managed
- Tetanus prophylaxis
- Antibiotics
- Emergency exploratory laparotomy
What are 6 indications for emergency exploratory laparotomy
- Extraviscation (organ outside)
- Peritonitis
- Haemodynamic instability
- Penetrating object in-situ
- PR bleed
- Free air under diraphragm
How is ATLS approach to trauma divided
- Primary survey
- Secondary survey
What is the primary survey approach
Used to look for injuries that will require immediate resuscitation
What is secondary survey
Used to scan for all other injuries
what may be looked for on secondary surgery in abdominal trauma
- Grey-turner’s sign
- Cullen’s sign
- Seatbelt sign
What is the seat belt sign
Presence of bruising in mark resembling lap portion of seatbelt
What is looked for on palpation in the secondary survey
Crepitus over lower ribs indicating splenic or liver damage
When is FAST imaging indicated for abdominal trauma
Immediate imaging as part of secondary survey for haemodynamically unstable patients
What is the problem with FAST scans
Poor at identifying retroperitoneal haemorrhage
When is diagnostic peritoneal lavage used for diagnosis
Haemodynamically unstable patients
What is the problem with diagnostic peritoneal lavage
May miss retroperitoneal haemorrhage and diaphragm injury
When is abdominal CT ordered
Stable patient
What is the advantage of abdominal CT
Good method for localising injury
What is fluid resuscitation
Individual is given 500mL crystalloid fluid challenge. Then given up to 2L fluid
How can individuals response to fluid be categorised
- Responder
- Transient responder
- Non-responder
What is a responder
Demonstrates physiological improvement on fluid
How much blood loss has a responder to fluid had
<20%
What is a transient responder
Someone who initially demonstrates an improvement on fluid and then deteriorates
How much blood loss has a transient responder had
20-40%
What will a transient responder require
Blood products
What is a non-responder
Someone who continues to deteriorate on fluid
How much blood loss has a non-responder had
> 40%